Energy consumption of microcontroller units (MCU) may be a significant factor in many applications, e.g. in battery-powered systems. In various applications, a MCU may be active for short time periods (for instance after a wake-up event) and switched to a low-power mode for the remaining time. When in a low-power mode, MCUs usually maintain the correct time and date.
Time and date may be used to wake-up a system at certain time intervals or may be exploited by the application itself. A hardware function in charge of maintaining time and date may be referred to as a Real-Time Clock (RTC). The consumption of a RTC may represent a significant portion of the overall system consumption when in low-power mode. Reducing RTC consumption may thus play a role in providing energy efficiency at the application level and improve battery duration.
Various microcontroller products may embed an RTC in association with functions such as, e.g., sensor sampling and management, metering, Internet of Things (IoT), and so on. General-purpose CPUs may also embed an RTC, but in that case power consumption may represent a less critical factor.